Asteroid 2023 DW: Can we deflect if it threatens Earth?
Wednesday, 15 March 2023 (14:56 IST)
"We've been tracking a new asteroid named 2023 DW that has a very small chance of impacting Earth in 2046," said NASA Asteroid Watch on its Twitter.
There's a "1 in 560 odds" chance of an impact, said NASA.
Or, to put it another — more positive — way, there's 99.8% chance that 2023 DW will safely fly by our planet and leave us in peace.
What is asteroid 2023 DW?
Asteroid 2023 DW was first observed on February 26, 2023.
Scientists think it's about 50 meters in diameter and currently 22 million kilometers (13.7 million miles) from Earth.
For reference, the moon orbits Earth, on average, at a distance of about 380,000 kilometers. That is a huge distance: Did you know, for instance, that you could fit all the planets of our solar system between the Earth and our moon and still have room to spare? Fun fact... But that's another story.
So, asteroid 2023 DW is a long way away from the Earth.
According to data from NASA's Center for Near Earth Object Studies (CNEOS), asteroid 2023 DW takes 271 days to orbit the sun.
But no orbit is a perfect circle. And in the case of this particular asteroid, its "eccentricity" — the amount by which it deviates from a circular orbit — means scientists think it could pass relatively near to Earth on Valentine's Day, February 14, 2046 — how romantic is that?
Current calculations put its nearest distance to Earth at 2,776,537 km.
You may have heard about asteroid #2023DW, but there’s no reason for concern: Our Center for Near Earth Object Studies (CNEOS) tracks all known near-Earth asteroids, and our experts are awaiting more observations of this new object to better refine its orbit around the Sun. https://t.co/9XH4CKJ8cj
Scientists need time to predict an asteroid's orbit
NASA's Eyes on Asteroids website shows real-time 3D visualizations and information about every known asteroid and comet that is classified as a near-Earth object.
Any small object in the solar system that can get relatively close to Earth is called a near-Earth object, or NEO for short.
If a NEO is larger than 140 meters wide and its orbit crosses the Earth's, it is called a potentially hazardous object, or PHO.
When new asteroids, such as 2023 DW, are detected, NASA says it needs quite a bit of time to gather enough data to "reduce the uncertainties and adequately predict their orbits years in the future."
That's because the longer and the more you observe, the better you can model how an asteroid moves around the sun and the better we can predict when it is likely to cross paths with Earth.
Why is the asteroid called 2023 DW?
Despite what you might think, the asteroid is unrelated to DW (Deutsche Welle).
The DW in its name is part of a standard, naming convention for the discovery of such "celestial" objects.
The first number relates to the year in which an object is discovered. In this case, it is the year 2023.
And the letters refer to the month and the order in which the object is discovered, with each month split into two halves.
So, January 1 to 15, for example, is the letter A.
And January 16 to 31 is the letter B.
So, the first object to be have been discovered in the first half of January 2023 was named 2023 AA, and the second 2023 AB, etcetera... until we get to 2023 DW, which was discovered in the second half of February and was the 23rd object to have been discovered.
Could NASA's DART technology stop asteroid 2023 DW from hitting the Earth?
On September 26, 2022, NASA successfully crashed a spacecraft into an asteroid in the first attempt of its kind to change the path of a celestial object.
The mission, named DART — Double Asteroid Redirection Test , hit Dimorphos, an asteroid that orbits a bigger asteroid called Didymos. Neither asteroid is a threat to Earth. But they were good for the test.
Dimorphos is about 160 meters in diameter — that's three times bigger than asteroid 2023 DW. For reference, the asteroid that wiped out the dinosaurs 66 million years ago is thought to have been about 10 kilometers wide.
"If a 160 meter asteroid [like Dimorphos] hits a city, it will a bad day for that city, leaving a crater of more than a kilometer," said Thomas Zurbuchen, then-associate administrator at NASA's Science Mission Directorate, in an interview with DW in November 2021 before DART launched.
CONFIRMED: Analysis of data obtained over the past 2 weeks by the #DARTMission team shows impact with Dimorphos has successfully altered the asteroid’s orbit by 32 minutes - marking the 1st time humans have changed the orbit of a celestial object in space! https://t.co/MjmUAFwVSOpic.twitter.com/4Qiy1mC4gK
DART was a proof-of-concept mission for the US National Near-Earth Object Preparedness Strategy and Action Plan, which aims to be prepared to defend the Earth in the event of a potential NEO impact.
In March 2023, NASA released its latest findings from the DART mission in a set of four papers. They concluded that DART's "asteroid deflection" technology, also known as a "kinetic impactor", altered Dimorphos' orbit and that it would remain the model for calculating any threats posed by future discovered asteroids.
But NASA says that it needs "sufficient warning time — several years at a minimum, but preferably decades." Which may mean that we could be in with a chance of deflecting the threat, no matter how small, from asteroid 2023 DW, given that we've got 23 years' time.
